We can never know enough about nutrition!
Check out this article from the CrossFit Journal. It talks about how those few poor decisions we make in a week can really sabotage your nutrition and, in turn, your fitness progress.
I recently started the Peeled Onion challenge and the biggest thing I've noticed so far is the importance of consuming an even balance of fats and carbs. The focus of the Peeled Onion challenge is to dial in your macro numbers rather than the quality of the foods. However, if you decide to eat a donut it's really going to screw up your day! For more information on the Peeled Onion challenge, go here!